My fast Nikkor lenses (50 1.8; 85 1.8; 80-200 2.8) have me eyeing a 2.8 replacement for my Sigma 18-200. I also have a Sigma 70-300 APO, so the two Sigmas (and eventually a Tokina 12-24) would make-up my "tourist" set while the Nikkors would take care of sports and more serious photography. But all this is contingent on finding good, affordable "fast" zoom glass. For those who have hands on experience (now or in the past), what do you/did you think of the Sigma 24-70mm f/2.8 EX DG Macro? Did Nikon make anything that was in the same range, better, and within 1.5-2x (used) of the sigmas $430 street price?